The present invention relates to a barcode printing system and its control method and, more particularly, to a barcode printing system for printing and checking barcodes, and a control method of the system.
Ink-jet printers form ejected inks by various schemes and attach them onto printing media such as recording paper sheets. Among such printers, ink-jet printers that use heat as energy for forming ejected inks have excellent features. That is, a plurality of ejection orifices can be arranged at high density, and such high-density arrangement allows to obtain a high-resolution, high-quality image at high speed and also to easily form a color image.
Of such ink-jet printers, the printers described in Japanese Patent Application Nos. 05-196196 and 06-110097 have a plurality of full-line type ink-jet print heads each having a width equal to that of the printing medium, and are applied to label printers and barcode printers that can obtain high-quality color images at high speed.
Since such printer produces a bubble in ink by heat energy in each ejection orifice, and directly ejects the ink from the ejection orifice of a print head by the pressure of the bubble, it is required to always maintain a stable ejection state of the ink.
However, ejection becomes unstable due to the influences of a bubble present in the ink, dried ink at the ejection orifice, attachment of paper dust onto the surface of the print head, and the like, resulting in non-ejection, mislanding of inks, and the like. In order to suppress non-ejection and mislanding of inks, such apparatus performs ink recovery at predetermined time intervals or exploits an improved recovery means, recovery sequence, and the like.
However, it is impossible to completely prevent non-ejection and mislanding of inks, and the printed image may often deteriorate due to non-ejection or mislanding of inks that occur suddenly.
In particular, when the printed image includes a barcode, print deterioration that does not pose any problem in a normal image may disturb reading of the image using a user's barcode reader.
In order to prevent the above-mentioned problem that the printed barcode cannot be read by the barcode reader, for example, the barcode reader is directly set at the downstream side of the printer convey path to read the printed bar code, after the printed barcode is read, the read barcode data is compared with printed barcode data to check if the barcode is OK/NG, and error processing is done if necessary.
However, in the method of comparing the printed barcode data and the read barcode data using the barcode reader, data transfer, data comparison, and the like between a control circuit of the printer and the barcode reader require much time. For this reason, during checking the barcode, printing must be interrupted or the print speed must be decreased, thus hampering high-speed printing. In order to realize high-speed data communications, a dedicated high-speed IF and the like must be inserted between the barcode reader and the control circuit, and the control circuit itself must use a high-speed CPU, resulting in high cost.